Content Handbook Q

Outline of method

The method involves preparing a suspension of the formulation in Standard Wa-ter. After standing under defined conditions the top 9/10ths are drawn off, and the remaining 1/10th is assayed. The spontaneity of dispersion is calculated as the percentage of active ingredient(s) remaining suspended.

To reflect the ease of forming a suspension and differently to the determination of suspensibility (MT 184.1), MT 160.1 applies only one inversion to form the suspension and reduces the standing time to 5 min.

Scope

This method is intended to determine the spontaneity of dispersion, which is defined as the percentage of one or more active ingredient(s) forming a suspension after limited agitation and remaining in suspension over a short period of time. The method is applicable to liquid formulations forming suspensions on dilution with water.

Reason for the revision

The method has been brought in line with MT 184.1 regarding general proce-dures, reagents, and equipment.

 A temperature requirement of 25 ± 5 °C has been set. The solvent extraction procedure has been removed.

Important note

Where same conditions are used, results obtained with MT 160.1 are equivalent to those obtained with MT 160.

MT 160.1 supersedes MT 160.